WESTERN-AUSTRALIAN FLY-ASH ON SANDY SOILS FOR CLOVER PRODUCTION

An experiment was conducted to determine the value of fly ash collecte d from flue gases of the Kwinana coal fired power station in Western A ustralia, as an amendment for sandy soils and as a replacement for pho sphorus or potassium fertilizers. The results showed large increases i n clover dry matter production (49% to 278%), attributed to improvemen ts in nutrient and water retention from the fly ash. The fly ash provi ded a substantial amount of the phosphorus needed by the clover, altho ugh application of phosphorus fertilizer further increased dry matter production in the presence of fly ash. No evidence was obtained from p lant growth or tissue analysis that the fly ash provided potassium to the pasture. The maximum yield was achieved when 50 t ha(-1) of fly as h was applied to the soil. However, only 10 to 40 t ha(-1) was require d to achieve 75 to 90% of the maximum production. Although a statistic ally significant increase in cadmium and mercury concentration could b e attributed to fly ash, the increase was small and within the range o f natural variation of levels found at the sites.